Flat roof of a sleeper cab of a truck vehicle



FIG. 1 is a left, front perspective view of a flat roof of a sleeper cab of a truck vehicle showing our new design;

FIG. 2 is a top view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof; and,

FIG. 5 is a left view thereof. 

The ornamental design for a flat roof of a sleeper cab of a truck vehicle, as shown and described. 